A dishwasher makes a perfect companion for an island sink. Put them close together, no more than a step apart, for convenience and so that they can share the same drain. A conventional dishwasher is one option, although its hinged, drop-down door may cause traffic jams. Slide-out dishwasher drawers (shown) take up a fraction of the floor space when open and come in a variety of sizes with one- and two-drawer configurations. The downside? They're not cheap.